The present invention relates generally to sheet materials which are cut-resistant, shred-resistant, and absorbent, and methods for making the same. More specifically, in one embodiment, the present invention relates to high basis weight paper structures which include randomly distributed polymer particles locked into the paper structure.
Protective materials having durability, such as cut-resistance and/or wear-resistance have been used for many applications. For instance, protective materials can be used as cutting boards to cover countertops during food preparation, such as when cutting meats or vegetables for cooking. Such protective materials can protect the food item from contacting contaminants which may reside on the support surface, such as a countertop. In addition, such a material can also protect the support surface from physical damage from a cutting tool, as well as from contamination from the food item being prepared.
However, many materials which are protective are not absorbent. For instance, a rigid plastic cutting board will not absorb juices from food items, and these juices may run off the cutting board and soil the countertop or support surface. In addition, many such materials are not flexible, and thus are not easily stored, manipulated, and disposed. Also, because many rigid cutting boards are not intended to be disposed after use, they require cleaning after each use.
On the other hand, many materials, such as paper-like materials, can exhibit high absorbency and flexibility and are disposable. However, such materials typically lose a significant amount of strength when wet, and thus cannot adequately protect a support surface from cutting forces. Also, such materials are not typically shred-resistant and thus, if used as a cutting board, particles from the material may transfer to the food item being prepared.
Accordingly, many materials which are highly cut and shred resistant are typically undesirable for use as disposable cutting sheets, due to the low flexibility and low absorbency typically inherent in such materials, as well as the high cost of such materials. Conversely, many materials which are highly flexible or absorbent and of lower cost, are typically undesirable for use in such applications due to the low cut and shred resistance inherent in such materials. For instance, plastic materials are high in cut and shred resistance but low in absorbency, while conventional paper materials are typically high in absorbency but low in cut and/or shred resistance, since paper fibers can be easily released as a cutting tool is drawn over the cutting surface.
Polymeric fibers have previously been utilized as a binder and strengthening agent in paper structures. Typically, in such paper structures, fibers made from hydrophobic polymers are added to paper fluff during paper formation. During drying of the mixture, the polymeric fibers flow and coat the surrounding paper fibers locking the paper fibers into the structure and significantly reducing the overall absorbency of the resulting structure. While the amount of polymer fiber could be reduced from the mixture to increase absorbency, such a solution compromises the cut-resistance and shred-resistance of the structure. Thus, one problem with such structures is that the amount of polymer fibers required to achieve adequate cut-resistance and/or shred-resistance significantly reduces the absorbency of the structure.
Accordingly, it is desirable to provide a sheet material which exhibits good absorbency and also good cut and shred resistance. It is also desirable to provide such a material that is also relatively flexible so as to be readily disposable, and easily dispensed, stored, and manipulated. In addition, it is desirable to provide such sheet materials which, while durable in use, can be economically manufactured so as to justify their disposal after each use.
It is an object of the present invention to obviate the above-described problems.
Another object of the present invention is to provide a disposable and protective cutting sheet.
It is a further object of the present invention to provide a sheet material that is absorbent, cut-resistant and shred-resistant.
Yet another object of the present invention is to provide a sheet material that can be used to slice food items, and which can effectively absorb juice from the food items while simultaneously resisting damage from a cutting tool.
A further object of the present invention is to provide a sheet material that is resistant to shredding and can absorb significant amounts of fluid produced by food items.
Another object of the present invention is to provide a cut-resistant, absorbent, shred-resistant sheet material that is readily disposable.
Yet another object of the present invention is to manufacture a cut-resistant, absorbent, shred-resistant sheet material using conventional equipment.
To achieve the foregoing and other objectives, and in accordance with one aspect of the invention, a cut-resistant, shred-resistant, and absorbent sheet material is provided. The sheet material comprises at least 50 percent by weight of an absorbent material. A plurality of cut-resistant particles that have an average size of at least about 100 micrometers are distributed throughout the absorbent material. The sheet material preferably has a basis weight of at least 100 pounds per 3000 ft2. It is also preferred that the absorbent material is substantially free of inorganic particulate filler.
According to another aspect of the invention, a method of forming a cut-resistant, shred-resistant, and absorbent sheet material is provided. The method comprises the steps of forming a mixture comprising absorbent fibers, non-fibrous polymeric particles, and water.
The polymeric particles have an average size of between about 100 and about 1000 micrometers, the absorbent fibers are provided in an amount of at least 50 percent by weight, and the mixture is substantially free of inorganic filler particulate. The mixture is formed into a sheet which is then dried. The dried sheet has a basis weight of at least 100 pounds per 3000 ft2. Preferably, the sheet is densified using heat and pressure to lock in the polymer particles and to improve cut and shred resistance.
According to another aspect of the invention, an absorbent and shred-resistant sheet material is provided comprising an absorbent substrate and cut-resistant particles dispersed through the absorbent substrate. The sheet exhibits a wet abrasion loss of less than about 400 mg per 100 revolutions and an absorbent efficiency of at least 0.2. It is preferred that the cut-resistant particles have an average size of at least about 100 micrometers. It is also preferred that the sheet has a basis weight of at least 100 pounds per 3000 ft2, that the absorbent substrate is provided in an amount of at least 50 percent by weight, and that the absorbent substrate is substantially free of inorganic particulate filler. Preferably, the sheet material exhibits a cut resistance of at least 30 kgf/cm.
Still other objects of the present invention will become apparent to those skilled in the art from the following description wherein there is shown and described preferred embodiments of this invention, including a best mode currently contemplated for carrying out this invention, simply for the purposes of illustration. As will be realized, the invention is capable of other different aspects and embodiments without departing from the scope of the invention. Accordingly, the drawings and descriptions are illustrative in nature and not restrictive in nature.